Liposuction of visceral fat using tissue liquefaction

ABSTRACT

Visceral fat may be removed from a subject using a cannula that has an interior cavity and an orifice configured to permit material to enter the cavity. This is accomplished by generating a negative pressure in the cavity so that a portion of the tissue is drawn into the orifice. Fluid is then delivered in pulses, via a conduit, so that the fluid exits the conduit within the cavity and impinges against the portion of the tissue that was drawn into the orifice. The fluid is delivered at a pressure and temperature that causes the visceral fat to soften, liquefy, or gellify, without damaging the subject&#39;s internal organs that are in the vicinity of the visceral fat. The visceral fat that has been softened, liquefied, or gellified is then suctioned away.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application61/065,187, filed Feb. 7, 2008; and this application is also acontinuation-in-part of U.S. application Ser. No. 12/112,233, filed Apr.30, 2008, which claims the benefit of U.S. provisional application60/915,027, filed Apr. 30, 2007.

BACKGROUND

It has come to light in the past 5 years that visceral fat is harmful togeneral health, whereas subcutaneous fat is not. Visceral fat is nowviewed as not just an inert blob of fat, but as another endocrine organ,a “bad” endocrine organ. The visceral fat secretes chemical mediatorswhich are believed to cause insulin resistance. Therefore visceral fatis now viewed as a culprit in the pathogenesis of diabetes mellitus typeII. Also, visceral fat is suspected to be a possible contributor tocardiovascular disease, cancer, and even aging itself.

Liposuction, also known as lipoplasty (fat modeling), liposculpture, orsuction lipectomy (suction-assisted fat removal) is a cosmetic surgeryoperation that removes subcutaneous fat from many different sites on thehuman body (e.g., the chest, buttocks, hips, thighs, or arms). Thetypical liposuction procedure relies on the shearing action of asharp-edged instrument to shear away the fatty deposits. The shearedfatty deposits are then suctioned away into orifices on the cannula.This process is labor intensive for the surgeon, traumatic to thepatient, and very time consuming.

Typical liposuction tools and methods cannot be used for visceral fatlipectomy in the same manner as they are used to remove subcutaneousfat, since visceral fat is attached to sensitive internal organs thatwill not tolerate the repeated thrusting and shearing required withtraditional lipectomy.

SUMMARY

With the methods and apparatuses described herein, visceral fat is drawninto orifices in a cannula, and a heated solution is impinged againstthose portions of visceral fat. The heated solution liquefies orgellifies parts of the visceral fat, so they can be removed from thepatient's body more easily.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a tissue liquefaction system.

FIG. 2 is a detail of the distal end of the FIG. 1 embodiment.

FIG. 3 is a section view of alternative configuration for the distal endof the FIG. 1 embodiment.

FIG. 4 is a detail of another alternative configuration for the distalend of the FIG. 1 embodiment.

FIGS. 5 and 5A show another embodiment of a tissue liquefaction system,which includes a forward-facing external tumescent spray applicator.

FIG. 6 shows some variations of the distal end of the cannula.

FIG. 7 shows how the cannula can be configured with externalfluid-supply paths, in less preferred embodiments.

FIG. 8 shows how the cannula can be configured with the fluid supplypaths internal to the suction path.

FIG. 9 shows a cannula with a single fluid supply tube internal to thesuction path

FIG. 10 shows a cannula configuration with two internal fluid supplytubes.

FIG. 11 shows a cannula having two fluid supply paths internal to thesuction path.

FIG. 12 shows a cannula with six fluid supply paths internal to thesuction path.

FIG. 13 shows an alternative cannula configuration with six internalfluid supply paths.

FIG. 14 is a block diagram of a suitable fluid heating andpressurization system.

FIG. 15 shows a high speed camera fluid supply image and pressure risegraph.

FIG. 16A shows an alternative cannula configuration with a single bend.

FIG. 16B shows an alternative cannula configuration with two bends.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments described below generally involve the delivery ofpressurized heated biocompatible fluid to heat targeted tissue andsoften, gellify, or liquefy the target tissue for removal from a livingbody. The heated biocompatible fluid is preferably delivered as a seriesof pulses, but in alternative embodiments may be delivered as acontinuous stream. After the tissue has been softened, gellified, orliquefied, it is sucked away out of the subject's body.

The interaction with the subject takes place at a cannula 30, examplesof which are depicted in FIGS. 1-4. The distal end of cannula ispreferably smooth and rounded for introduction into the subject's body,and the proximal end of the cannula is configured to mate with ahandpiece 20. The cannula 30 has an interior cavity with one or moreorifice ports 37 that open into the cavity. These orifices 37 arepreferably located near the distal portion of the cannula 30. When a lowpressure source is connected up to the cavity via a suitable fitting,suction is generated which draws target tissue into the orifice ports37.

The cannula also includes one or more fluid supply tubes 35 that directthe heated fluid onto the target tissue that has been drawn into thecavity. These fluid supply tubes are preferably arranged internally tothe outside wall of the cannula (as shown in FIG. 8), but in alternativeembodiments may be external to the cannula for a portion of the lengthof the supply tube (as shown in FIG. 7). The heated fluid supply tubes35 preferably terminate within the outside wall of the cannula, in thevicinity of the suction orifice ports 37. The fluid supply tubes 35 arearranged to spray the fluid across the orifice ports 37 so that thefluid strikes the target tissue that has been drawn into the cavity.Delivery of the tissue fluid stream is preferably contained within theouter wall of the cannula.

The fluid delivery portion may be implemented using a fluid supplyreservoir 4, a heat source 8 that heats the fluid in the reservoir 4,and a temperature regulator 9 that controls the heat source 8 asrequired to maintain the desired temperature. The heated fluid from thefluid supply 4 is delivered under pressure by a suitable arrangementsuch as a pump system 19 with a pressure regulator 11. Optionally, aheated fluid metering device 12 may also be provided to measure thefluid that has been delivered.

Pump 19 pumps the heated fluid from the reservoir or fluid supply source4 down the fluid supply tubes 35 that run from the proximal end of thecannula 30 down to the distal end of the cannula. Near the distal tip ofthe cannula, these fluid supply tubes preferably make a U-turn so as toface back towards the proximal end of the cannula 30. As a result, whenthe heated fluid exits the supply tube 35 at the supply tube's deliveryorifice 43, the fluid is traveling in a substantially distal-to-proximaldirection. Preferably, the pump delivers a pressurized, pulsating outputof heated fluid down the supply tube 35 so that a series of boluses offluid are ejected from the delivery orifice 43, as described in greaterdetail below.

The vacuum source and the fluid source interface with the cannula 30 viaa handpiece 20. The heated solution supply is connected on the proximalside of hand piece 20 with a suitable fitting, and a vacuum supply isalso connected to the proximal side of handpiece 20 with a suitablefitting. Cannula 30 is connected to the distal side of hand piece 20with suitable fittings so that (a) the heated fluid from the fluidsupply is routed to the supply tubes 35 in the cannula and (b) thevacuum is routed from the vacuum source 14 to the cavity in the cannula,to evacuate material from the cavity.

More specifically, the pressurized heated solution that is dischargedfrom pump 19 is connected to the proximal end of the handle 20 via highpressure flexible tubing, and routed through the handpiece 20 to thecannula 30 with an interface made using an appropriate fitting. Thevacuum source 14 is connected to an aspiration collection canister 15,which in turn is connected to the proximal end of the handle viaflexible tubing 16, and then routed through the handpiece 20 to thecannula 30 with an interface made using an appropriate fitting. Thepressurized fluid supply line connection between the handle and thecannula 30 may be implemented using a high pressure quick disconnectfitting located at the distal end of the handle, and configured so thatonce the cannula is inserted into the distal end of the handle it alignsand connects with both the fluid supply and the vacuum supply. Thecannula 30 may be held in place on the handle 20 by an attachment cap.

As best seen in FIG. 3, after the cannula 30 is inserted into the body;vacuum source 14 creates a low pressure region within cannula 30 suchthat the target fatty tissue is drawn into the cannula 30 throughsuction orifice 37. The geometry of the end of the supply tube 35 isconfigured so the trajectory of the boluses leaving the delivery orificewill strike the fatty tissue that has been drawn into the cannula 30through suction orifice 37. For that purpose, the end of the supply tubepreferably points in direction that is substantially parallel to that ofthe inside wall of the cannula 30 where it is affixed. Preferably, it isoriented that the stream flows across the orifice in a distal toproximal direction. This placement of the tip 43 of the supply tube 35advantageously maximizes the energy transfer (kinetic and thermal) tothe fatty tissues, minimizes fluid loss, and helps prevent clogs bypushing the heated fluid and the liquefied/gellified/softened materialin the same direction that it is being pulled by the vacuum source.

Once the targeted fatty tissue enters the suction orifice 37, it isrepeatedly struck by the boluses of heated fluid that are exiting thesupply tubes 35 via the delivery orifice 43. The target fatty tissue isheated by the impinging boluses of fluid and is softened, gellified, orliquefied. After that occurs, the loose material in the cavity (i.e.,the heated fluid and the portions of tissue that were dislodged by thefluid) is drawn away from the surrounding tissue by the vacuum source14, and deposited into the canister 15 (shown in FIG. 1).

Advantageously, fat is more readily softened, gellified, or liquefied(as compared to other types of tissue), so the process targets fat morethan other types of tissue. Note that the distal-to-proximal directionof the boluses is the same as the direction that the liquefied/gellifiedtissue travels when it is being suctioned out of the patient via thecannula 30. By having the fluid stream flow in the distal to proximaldirection, additional energy (vacuum, fluid thermal and kinetic) istransferred in the same direction, which aids in moving the aspiratedtissues through the cannula. This further contributes to reducing clogs,which can reduce the time it takes to perform a procedure.

Notably, in the embodiments described herein, the majority of the fluidstays within the interior of the cannula during operation (although asmall amount of fluid may escape into the subject's body through thesuction orifices 37). This is advantageous because minimizing fluidleakage from the cannula into the tissue maximizes the energy transfer(thermal and kinetic) from the fluid stream to the tissue drawn into thecannula for liquefaction.

The fluid supply portion of the system will now be described withadditional detail. FIG. 3 depicts a cut-away view of an embodiment ofthe cannula 30 that has two supply tubes 35. Each of the supply tubes 35is provided for delivering the heated fluid. Supply tube 35 extends fromthe proximal portion of cannula 30 to the distal tip 32 of cannula 30.Supply tube 35 extends along the interior of cannula 35 and may be aseparate structure secured to the interior of cannula 35 or lumenintegrated into the wall of cannula 30. Supply tube 35 is configured todeliver heated biocompatible solution for liquefying tissue. The heatedsolution is delivered through hand piece 20 and into supply tube 35.

The supply tube 35 extends longitudinally along axis 33 from theproximal end 31 to the distal tip 32. Supply tube 35 includes U-bend 41,effectively turning the run of the supply tube 35 along the inner wallof the distal tip 32. Adjacent the terminal end of u-bend 41 is supplytube terminal portion 42, which includes delivery orifice 43. Deliveryorifice 43 is configured to direct heated solution exiting supply tube35 across suction orifice port 37. In this manner, supply tube 35 isconfigured to direct the fluid onto a target tissue that has entered thecannula 30 through the suction orifice port 37.

Heated solution supply tube 35 may be constructed of surgical gradetubing. Alternatively, in embodiments wherein the heated solution supplytube is integral to the construction of cannula 30, the supply tube 35may be made of the same material as cannula 30. The diameter of supplytube 35 may be dependent on the target tissue volume requirements forthe heated solution and on the number of supply tubes required todeliver the heated solution across the one or more suction orifice ports37. The cannula 30 tube diameters vary with the cannula outsidediameters and those can range from 2-6 mm. The fluid supply tube 35diameters are dependent on the inside diameters of the tubes. Apreferred range of supply tube 35 diameters is from about 0.008″ to0.032″. In one preferred embodiment, the supply tube 35 is a 0.02″diameter for the length of the cannula 30, with an exit nozzle formed byreducing the diameter to 0.008″ over the last 0.1″. The shape and sizeof delivery orifice 43 may vary, including reduced diameter andflattened configurations, with the reduced diameter being preferred.

In alternative embodiments, the cannula 30 may have a different numberof heated solution supply tubes 35, each corresponding to a respectivesuction orifice port. For example, a cannula 30 with three suctionorifice ports 37 would preferably include three heated solution supplytubes 35. Additionally, heated solution supply tubes may be added toaccommodate one or more suction orifice ports, e.g., when four suctionorifice ports are provided, four heated solution supply tubes may beprovided. In another embodiment, a supply tube 35 may branch intomultiple tubes, each branch servicing a suction orifice port. In anotherembodiment, one or more supply tubes may deliver the heated fluid to asingle orifice port. In yet another embodiment, supply tube 35 may beconfigured to receive one or more fluids in the proximal portion ofcannula 30 and deliver the one or more fluids though a single deliveryorifice 43. In another embodiment, the cannula may be attached to anendoscope or other imaging device. In yet another embodiment depicted inFIGS. 5 and 5A, cannula 30 may include a forward-facing external fluiddelivery applicator 45 in addition to the distal-to-proximal fluidsupply tube 35.

The heated fluid should be biocompatible, and may comprise a sterilephysiological serum, saline solution, glucose solution, Ringer-lactate,hydroxyl-ethyl-starch, or a mixture of these solutions. The heatedbiocompatible solution may comprise a tumescent solution. The tumescentsolution may comprise a mixture of one or more products producingdifferent effects, such as a local anesthetic, a vasoconstrictor, and adisaggregating product. For example, the biocompatible solution mayinclude xylocalne, marcaine, nesacaine, Novocain, diprivan, ketalar, orlidocaine as the anesthetic agent. Epinephrine, levorphonal,phenylephrine, athyl-adrianol, or ephedrine may be used asvasoconstrictors. The heated biocompatible fluid may also comprisesaline or sterile water or may be comprised solely of saline or sterilewater.

FIG. 14 depicts one example of a suitable way to heat the fluid anddeliver it under pressure. The components in FIG. 14 operate using thefollowing steps: Room temperature saline drains from the IV bag 51 intomixing storage reservoir 54. Once the fluid in the reservoir 54 reachesa fixed limit, the fixed speed peristaltic pump 55 of the heater system8 moves fluid from the reservoir 54 to the heater bladder 56. The fluidis circulated through the bladder and is heated by the electric panels57 of the heater system 8. The heated fluid is returned back to thereservoir 54 and mixes with the other fluid in the storage container.The fixed speed peristaltic pump 55 continues to circulate fluid to theheater unit and back into the reservoir 54. The continuous circulationof fluid provides a very stable and uniform heated fluid volume supply.Temperature control may be implemented using any conventional technique,which will be readily apparent to persons skilled in the relevant arts,such as a thermostat or a temperature-sensing integrated circuit. Thetemperature may be set to a desired level by any suitable userinterface, such as a dial or a digital control, the design of which willalso be apparent to persons skilled in the relevant arts.

The pump 58 may be a piston-type pump that draws heated fluid from thefluid reservoir 54 into the pump chamber when the pump plunger travelsin a backstroke. The fluid inlet to the pump has an in-line one-waycheck valve that allows fluid to be suctioned into the pump chamber, butwill not allow fluid to flow out. Once the pump plunger backstroke iscompleted, the forward travel of the plunger starts to pressurize thefluid in the pump chamber. The pressure increase causes the one-waycheck valve at the inlet of the pump 58 to shut preventing flow fromgoing out the pump inlet. As the pump plunger continues its forwardtravel the fluid in the pump chamber increases in pressure. Once thepressure reaches the preset pressure on the pump discharge pressureregulator the discharge valve opens. This creates a bolus of pressurizedheated fluid that travels from the pump 58 through cannula handle 20 andfrom there into the supply tube 35 in the cannula 30. After the pumpplunger has completed its forward travel the fluid pressure decreasesand the discharge valve shuts. These steps are then repeated to generatea series of boluses. Suitable repetition rates (i.e., pulse rates) arediscussed below.

One example of a suitable approach for implementing the positivedisplacement pump is to use an off-set cam on the pump motor that causesthe pump shaft to travel in a linear motion. The pump shaft is loadedwith an internal spring that maintains constant tension against theoff-set cam. When the pump shaft travels backwards towards the off-setcam it creates a vacuum in the pump chamber and suctions heated salinefrom the heated fluid reservoir. A one-way check valve is located at theinlet port to the pump chamber, which allows fluid to flow into thechamber on the backstroke and shuts once the fluid is pressurized on theforward stroke. Multiple inlet ports can allow for either heated orcooled solutions to be used. Once the heated fluid has filled the pumpchamber at the end of the pump shaft backwards travel, the off-setportion of the cam will start to push the pump shaft forward. The heatedfluid is pressurized to a preset pressure (e.g. 1100 psi) in the pumpchamber, which causes the valve on the discharge port to open,discharging the pressurized contents of the pump chamber to fluid supplytubes 35. Once the pump plunger completes its full stroke based on theoff-set of the cam, the pressure in the pump chamber decreases and thedischarge valve closes. As the cam continues to turn the process isrepeated. The pump shaft can be made with a cut relief, which will allowthe user to vary the boluses size. The cut off on the shaft will allowfor all the fluid in the pumping chamber to be ported through thedischarge path to the supply tubes or a portion of the pressurized fluidto be ported back to the reservoir.

The heated biocompatible solution in a tissue liquefaction system ispreferably delivered in a manner optimized for softening, gellifying, orliquefying the target tissue. Variable parameters include, withoutlimitation, the temperature of the solution, the pressure of thesolution, the pulse rate or frequency of the solution, and the dutycycle of the pulses or boluses within a stream. Additionally, the vacuumpressure applied to the cannula through vacuum source 14 may beoptimized for the target tissue.

It has been found that for liposuction procedures targeting subcutaneousfatty deposits within the human body, the biocompatible heated solutionshould preferably be delivered to the target fatty tissue at atemperature between 75 and 250 degrees F., and more preferably between110 and 140 degrees F. A particular preferred operating temperature forthe heated solution is about 120 degrees F., since this temperatureappears very effective and safe. Also, for liquefaction of fattydeposits the pressure of the heated solution is preferably between about200 and about 2500 psi, more preferably between about 600 and about 1300psi, and still more preferably between about 900 and about 1300 psi. Aparticular preferred operating pressure is about 1100 psi, whichprovides the desired kinetic energy while minimizing fluid flow. Thepulse rate of the solution is preferably between 20 and 150 pulses persecond, more preferably between 25 and 60 pulses per second. In someembodiments, a pulse rate of about 40 pulses per second was used. Andthe heated solution may have a duty cycle (i.e., the duration of thepulses divided by the period at which the pulses are delivered) ofbetween 1-100%. In preferred embodiments, the duty cycle may rangebetween 30 and 60%, and more particularly between 30 and 50%.

In preferred embodiments, the rise rate (i.e., the speed with which thefluid is brought to the desired pressure) is about 1 millisecond orfaster. This may be accomplished by having a standard relief valve thatopens once the pressure in the pump chamber reaches the set point(which, for example, may be set to 1100 psi). As shown in FIG. 15, thepressure increase is almost instantaneous, as evidenced by the spikerepresenting the rise rate in the pressure rise graph (inset). FIG. 15further illustrates how the fluid exits the fluid supply tubes during avery short time span.

Returning now to the suction subsystem, FIG. 3 depicts an expandedcut-away view of an embodiment that includes two suction orifices. Asshown, the cannula 30 has two suction orifices 37 located near thedistal region of the cannula 30 and proximal to distal tip 32. Suctionorifice ports 37 may be positioned in various configurations about theperimeter of the distal region of cannula 30. In the illustratedembodiment, the suction orifice ports 37 are on opposite sides of tilecannula 30, but in alternative embodiments they may be positioneddifferently with respect to each other. Suction orifice ports 37 areconfigured to allow fatty tissue to enter the orifices in response tolow pressure within the cannula shaft created by vacuum supply 14. Thematerial that is located in the cavity (i.e., tissue that has beendislodged and the heated fluid that exited the supply tube 35) is thensuctioned away in a proximal direction up through the cannula 30, thehandpiece 20, and into the canister 15 (all shown in FIG. 1). Aconventional vacuum pump (e.g., the AP-III HK Aspiration Pump from HKsurgical) may be used for the vacuum source.

In preferred embodiments, the aspiration vacuum that sucks theliquefied/gellified tissue back up through the cannula ranges from0.33-1 atmosphere (1 atmosphere=760 mm Hg). Varying this parameter isnot expected to effect any significant changes in system performance.Optionally, the vacuum level may be adjustable by the operator duringthe procedure. Because reduced aspiration vacuum is expected to lowerblood loss, operator may prefer to work at the lower end of the vacuumrange.

Returning to FIGS. 1-4, the cannula 30 and handpiece 20 will now bedescribed in greater detail. Hand piece 20 has a proximal end 21 and adistal end 22, a fluid supply connection 23 and a vacuum supplyconnection 24 preferably located at the proximal end, and a fluid supplyfitting and a vacuum supply fitting at the distal end (to interface withthe cannula). The hand piece 20 routes the heated fluid from the fluidsupply to the supply tubes 35 in the cannula and routes the vacuum fromthe vacuum source 14 to the cavity in the cannula, to evacuate materialfrom the cavity.

In some embodiments, a cooling fluid supply 6 may be used to dampen theheat effect of the heated fluid stream in the surgical field. In theseembodiments, the handpiece also routes the cooling fluid into thecannula 35 using appropriate fittings at each end of the handpiece. Inthese embodiments, a cooling fluid metering device 13 may optionally beincluded. The hand piece 20 may optionally include operational andergonomic features such as a molded grip, vacuum supply on/off control,heat source on/off control, alternate cooling fluid on/off control,metering device on/off control, and fluid pressure control. Hand piece20 may also optionally include operational indicators including cannulasuction orifice location indicators, temperature and pressureindicators, as well as indicators for delivered fluid volume, aspiratedfluid volume, and volume of tissue removed. Alternatively, one or moreof the aforementioned controls may be placed on a separate controlpanel.

The distal end 22 of hand piece 20 is configured to mate with thecannula 30. Cannula 30 comprises a hollow tube of surgical gradematerial, such as stainless steel, that extends from a proximal end 31and terminates in a rounded tip at a distal end 32. The proximal end 31of the cannula 30 attaches to the distal end 22 of hand piece 20.Attachment may be by means of threaded screw fittings, snap fittings,quick-release fittings, frictional fittings, or any other attachmentconnection known in the art. It will be appreciated that the attachmentconnection should prevent dislocation of cannula 30 from hand piece 20during use, and in particular should prevent unnecessary movementbetween cannula 30 and hand piece 20 as the surgeon moves the cannulahand piece assembly in a back and forth motion approximately parallel tothe cannula longitudinal axis 33.

The cannula may include designs of various diameters, lengths,curvatures, and angulations to allow the surgeon anatomic accuracy basedupon the part of the body being treated, the amount of fat extracted aswell as the overall patient shape and morphology. This would includecannula diameters ranging from the sub millimeter range (0.25 mm) fordelicate precise liposuction of small fatty deposits to cannulas withdiameters up to 2 cm for large volume fat removal (i.e. abdomen,buttocks, hips, back, thighs etc.), and lengths from 2 cm for smallareas (i.e. eyelids, cheeks, jowls, face etc.) up to 50 cm in length forlarger areas and areas on the extremities (i.e. legs, arms, calves,back, abdomen, buttocks, thighs etc.). A myriad of designs include,without limitation, a C-shaped curves of the distal tip alone, S-shapedcurves, step-off curves from the proximal or distal end as well as otherlinear and nonlinear designs. The cannula may be a solid cylindricaltube, articulated, or flexible.

Each of the suction orifice ports 37 includes a proximal end 38, adistal end 39, and a suction orifice port perimeter 40. Although theillustrated suction orifices are oval or round, in alternativeembodiments they may be made in other shapes (e.g., egg shaped, diamondor polygonal shaped, or an amorphous shape). As depicted in FIG. 3, thesuction orifice ports 37 may be arranged in a linear fashion on one ormore sides of cannula 30. Alternatively, the suction orifice ports 37may be provided in a multiple linear arrangement, as depicted in FIG. 4.Optionally, the dimensions or shape of each suction orifice port maychange, for example, from the most distal suction orifice port to themost proximal, as illustrated in FIG. 4, where the diameter of eachsuction orifice port may decrease in succession from the distal port tothe proximal port.

In some embodiments, the suction orifice perimeter edge 40 is configuredto present a smooth, unsharpened edge to discourage shearing, tearing orcutting of the target fatty tissue. Because the target tissue isliquefied/gellified/softened; the cannula 30 does not need to sheartissue as much as found in traditional liposuction cannulas. In theseembodiments, the perimeter edge 40 is duller and thicker than typicallyfound in prior-art liposuction cannulas. In alternative embodiments, thecannula may use shearing suction orifices, or a combination ofreduced-shearing and shearing suction orifice ports. The suction orificeport perimeter edge 40 of any individualized suction orifice port mayalso be configured to include a shearing surface or a combination ofshearing and reduced-shearing surfaces, as appropriate for theparticular application.

Using between one and six suction orifices 37 is preferable forsubcutaneous fat, and using two or three suction orifices is morepreferable. The suction orifices may be made in different shapes, suchas round or oblong. FIG. 6 shows some exemplary suction orifices ofdifferent size. Cross section F is shown with a standard shearingorifice port 37. Cross section G has a larger shearing orifice port 37,while cross section H has a perimeter with a smooth and unsharpened edgeto discourage shearing. When oblong suction orifices are used, the longaxis should preferably be oriented substantially parallel to thedistal-to-proximal axis. The suction orifices should not be too large,because with smaller suction orifices less fat is suctioned into thecannula for a given bolus of energy. On the other hand they should notbe too small, to permit the fatty tissue to enter. A suitable size rangefor circular suction orifices is between about 0.04″ and 0.2″. Asuitable side for oblong suction orifices is between about 0.2″×0.05″and about ½″×?″. The size of the suction orifices can further be variedfor different applications depending on the surgeon's requirements. Moreextensive areas to be suctioned may require larger orifices whichrequire more shearing surface.

As shown in FIGS. 7-13, the surface area of a unit length of the suctionpath can be calculated by multiplying the total perimeter of the suctionpath by a unit length. An exemplary perimeter of the suction path isp(4.115 mm), which when multiplied by 1 mm length, gives a unit lengtharea of 12.9 mm². FIG. 7 shows the diameter of the inside of the suctionpath (which would then be multiplied by p to give the perimeter lengthand then by a unit length of 1 mm to give the surface area of 12.93).For the embodiment shown in FIG. 7, the resistance ratio of the suctionpath calculates to be 12.92 mm²/13.30 mm²=0.97. And the resistance ratioof the fluid path (both tubes included) calculates to be: 5.10 mm²/1.04mm²=4.90. Comparing resistive ratios, with the first passage beingdefined as the suction path, in the FIG. 7 embodiment, we see that thecomparative resistance ratio is 0.97/4.90=0.20.

For the embodiment shown in FIG. 8, the calculated resistance ratio ofthe suction path is 1.68 and the calculated resistance ratio of thefluid path (both tubes included) is 4.92. Accordingly, the comparativeresistance ratio is 0.38. Similarly, in FIG. 9, the suction resistanceratio is 1.11 and the fluid resistance ratio 4.61, so the comparativeresistance ratio is 0.24. In FIG. 10, the suction resistance ratio is1.20 and the fluid resistance ratio 5.98, so the comparative resistanceratio equals 0.20. In FIG. 11, the suction resistance ratio is 1.31 andthe fluid resistance ratio is 4.65, so the comparative resistance ratiois 0.28. In FIG. 12, the suction resistance ratio is 2.25 and the fluidresistance ratio 7.88, so the comparative resistance ratio is 0.29. InFIG. 13, the suction resistance ratio is 1.23 and the fluid resistanceratio is 10.23, so the comparative resistance ratio is 0.12.

The general principles described above may be optimized for removingvisceral fat from a subject's body. However, since visceral fat islocated on and around organs that are more delicate than the tissue inwhich subcutaneous fat is found, care must be taken to minimize traumato the relevant anatomical regions, to permit removal the visceral fatwithout causing damage or trauma to the adjacent internal organs. Forexample, the orifice ports should preferably have blunt edges (asopposed to sharp edges) for this use, so as to avoid shearing andcutting of tissue, and the pressure and temperature ranges should beselected to avoid trauma.

The straight cannula embodiments described above may be used forremoving visceral fat. Preferably, the cannula tubing is constructedfrom cylindrical, elliptical, or flat face tubing, with no exaggeratedblunt faces. Suitable materials for the cannula body include surgicalgrade metallic materials like 304 and 316 stainless steel, as well asshape memory and super elastic metallic materials like Nitinol. Thecannula can also be made of non-metallic materials like Peek,polycarbonate, high density polyethylene, nylon, and other highdurometer plastics.

The cannula can be constructed with and without an outer sleeve that isbraided, coiled, or continuous. The sleeve can be made out of Teflon orother flexible polymeric materials like urethane, nylon, and others. Thesleeve can also be made of thin wall metallic materials like stainlesssteel and Nitinol in a non-continuous (coil or braid) to provideflexibility. The cannula can also be constructed of a multi layerpolymer and metallic combination, such as a Teflon base inner layer witha metallic braid or coil middle layer and a polymeric outer layer likenylon or urethane. This would be similar to existing coronary guidingcatheter technologies like the one used in Cordis Vista Brite TipGuiding Catheters and endoscopes like the one used in the Olympus FiberOptic Lines (BF-XP60).

Suitable dimensions for the cannula diameter range from 2.0 mm for smalldelicate fatty deposits to 20 mm for large volume fat removals likeOmentectomy. For open surgical procedures the entire range of cannulasized can be used. For laparoscopic or approaches requiring passagethrough other conduits or trocar sheaths, the cannula diameter rangeshould be 2.0-12.0 mm sizes, based on currently used abdominal trocarand access cannula sizes.

Suitable dimensions for the cannula diameter length range from 2.0 cmfor open surgical procedures to 50 cm for laparoscopic or proceduresrequiring access through other cannula sheaths.

The cannula preferably has between 1 and 6 orifice ports, which may bespaced on the same side or around the circumference. More preferably,between 1 and 4 orifice ports are used, all positioned on the bottom(i.e., the tissue contact surface). The most preferred visceral cannulahas 1 or 2 openings, all positioned on the bottom so as to minimizepulling in non-target tissues and allow greater control to the surgeon.

The opening shapes can be circular, elliptical, rectangular, andtriangular or many other geometrical shapes. One preferred opening shapeis an elongated elliptical shape. The size of the opening can vary forany given cannula diameter and length. The opening diameter ispreferably smaller than half of the cannula diameter and the length maybe order of three quarters of the cannula diameter or less. Preferably,the orifice ports have blunt edges to minimize any trauma to non-targettissues.

Optionally, one or more bends may be incorporated into the cannula, asshown in FIGS. 16A and 16B. Preferably the distal-most bend is proximalto the proximal-most orifice port. The bends are preferably configuredto aid the surgeon in the insertion and manipulation of the cannula, toconform to the particular anatomic region being treated. The bends mayeither be abrupt (e.g., bent like a hockey stick), as illustrated inFIGS. 16A and 16B, or have a larger radius of curvature (e.g., bent likethe handle of a walking cane), depending on the anatomic region beingtreated.

FIGS. 16A and 16B illustrate two embodiments of a cannula for visceralfat applications, and similar reference numbers are used to describeboth of those embodiments. Cannula 30 comprises a hollow tube thatextends from a proximal end 31 and terminates in a rounded tip at adistal end 32. FIG. 16A shows a cannula with a single bend 46, whereasFIG. 16B shows a cannula with two bends 46, and additional bends may beincluded in alternative embodiments if so desired. The bends 46 arepreferably proximal to all the orifice ports 37. In the bentembodiments, the bend angle is preferably between 5 and 85 degrees. Theoptimum bend angle will depend on the particular procedure beingperformed. For open surgical procedures, larger angles (e.g., between 45and 85 degrees) are more suitable, more preferably between 55 and 75degrees. For laparoscopic procedures that require the cannula to beinserted through other cannulas or sheaths, smaller angles (e.g.,between 5 and 45 degrees) are more suitable, more preferably between 15and 35 degrees. For open surgical procedures, the length of the distalsection of the cannula past the bend is preferably between 1 and 4inches. For laparoscopic procedures, the length of the distal section ofthe cannula past the bend is preferably between 1 and 2 inches.

In the illustrated embodiments, the cannula 30 has two orifice ports 37located near the distal region of the cannula 30 and proximal to thedistal tip 32, disposed on opposite sides of the cannula 30. However inalternative embodiments, the orifice ports 37 may be positioned indifferent configurations about the perimeter of the distal region ofcannula 30. For example, a different number of orifice ports (e.g., 1-6)may be used, disposed at different angles (e.g., 70° apart) or all onthe same side (i.e., 0° apart).

The orifice ports 37 are configured to allow fatty tissue to enter theport in response to low pressure within the cannula shaft created byvacuum supply 14. Orifice ports 37 include a proximal end 38, a distalend 39, and an orifice port perimeter edge 40. Orifice ports 37 may takea generally circular, oval or egg shape, diamond or polygonal shape, oran amorphous shape. In the illustrated embodiments, the orifice ports 37are oval and are all the same size. In alternative embodiments, thedimensions or shape of the orifice ports may vary within a singlecannula, like the cannula shown in FIG. 4, in which the diameter of eachorifice port decreases in succession from the distal end to the proximalend.

In both the straight and bent embodiments, the cannula may be made ofround tubing or tubing with one or more flat surfaces. The distal end ofthe cannula may be integrally formed as a continuation of the shaft orit can be a two piece construction, with a metal or polymer tip affixedto the end of the shaft. Polymer tips can be advantageous because theyare softer than metal. Examples of suitable materials for the tipinclude, but are not limited to nylon and high density polyethylene.

In alternative embodiments (not shown), one or more articulation jointsmay be incorporated into the cannula. Preferably, these articulationjoints are provided proximal to the proximal-most orifice. One suitableway to implement these articulating embodiments is to replace a portionof the cannula from a point that is proximal of the proximal-mostorifice with a flexible tubing, and then running that flexible tubingthrough a conventional articulation joint. In these embodiments, theflexible tubing should be selected or reinforced so as not to collapseunder the vacuums expected to be encountered. Examples of suitablearticulation joints can be found in U.S. Pat. Nos. 4,108,211 and7,090,637, each of which is incorporated herein by reference as if setforth herein in its entirety. Other examples include the bendingmechanisms used in endoscopes like the Olympus Fiber Optic Lines(BF-XP60) and in other articulating devices like the Medtronic HeartWall Ablation Catheters (RF Conductr (MC) Series). Any suitableconventional control mechanism may be used to bend the articulationjoints, depending on the articulation joint that is used. Examplesinclude foot pedals and hand controls.

When articulation joints with bending mechanisms are incorporated, theoperator is able to control the position of distal end of the cannula.For example, if an articulation joint with a single degree of freedom isused, the operator would be able to bend the joint back and forth, likea windshield wiper so as to move the distal end in an arc. A suitablerange of motion is 90° of bending (i.e., ±45°), but smaller or largerarticulation angles may be implemented, e.g., up to 180° of bending(i.e., ±90°).

If an articulation joint with two perpendicular degrees of freedom isused, the operator would be able to bend the joint back and forth, andwould also be able to move the distal end of the probe up and down in adirection that is perpendicular to the plane of the wiping motion. Theseembodiments permit manipulation of the cannula's distal end inthree-dimensional space, providing additional fine-tuned control ofmovement, which can be particularly desirable when removing visceral fatfrom around intestinal structures. A suitable range of motion in theup/down direction is 45° of bending, but smaller or larger articulationangles may be implemented, e.g., 80° of bending. Optionally, the bendingmay be controlled by a mechanized, motorized unit under direct controlof the surgeon.

The visceral fatty tissue lipectomy of the present invention should betarget tissue-specific so as to remove the visceral fat without damagingthe surrounding organs and tissue. To accomplish this, the temperatureof the solution is preferably between 75 and 250° F., more preferablybetween 75 and 190° F., still more preferably between 100 and 140° F.,and most preferably about 120° F. The stream pressure is preferablybetween 300 and 2000 psi, more preferably between 600 and 1300 psi,still more preferably between 900 and 1300 psi, and most preferablyabout 1100 psi. The fluid should preferably be delivered in pulses, witha preferred pulse rate between 25 and 60 pulses per second, morepreferably about 40 pulses per second. The preferred duty cycle forthese pulses is between about 30 and 80%, more preferably about 30% tominimize the amount of waste fluid that is generated. The preferred riserate for the pulses is about 1 millisecond or less. The aspiration(vacuum) is preferably between ⅓ and 1 atmosphere, and more preferablybetween ⅓ and ¾ atmosphere.

In the most preferred embodiments for removing visceral fat, thetemperature of the solution is between 100 and 140° F., and it isdelivered in pulses at a stream pressure between 900 and 1300 psi at apulse rate between 25 and 60 pulses per second. This combination ofparameters provides good tissue differentiation, so as to facilitateremoval of the visceral fat without causing trauma to the delicateanatomic structures in the vicinity.

To perform removal of visceral fat, the cannula is inserted into theabdomen via an open surgical procedure or through a smaller laparoscopicincision. In the latter case, the visceral fat is preferably visualizedby a laparoscopic camera using any suitable conventional visualizationtechnology.

Optionally, surgical field cleaning fluids such as water or saline maybe delivered to the site being treated. Alternatively or in addition, asmall amount of liposuction tumescent fluid (containing, e.g.,epinephrine, lidocaine, levorphonal, phenylephrine, athyl-andrianol,ephedrine, or other vasoconstrictors and/or xylocalne, marcaine,nesacaine, Novocain, diprivan, ketalar, ladocaine, or other anestheticagents and/or other suitable chemicals) may be introduced into theregion that is being treated. One suitable way to introduce such fluidsinto the desired region is to include a dedicated conduit that is builtinto the cannula, with a forward-facing exit port similar to the port 45shown in FIGS. 5 and 5A. In alternative embodiments a separate cathetermay be used to introduce the desired fluids. These infusions arepreferably implemented using low pressure peristaltic type pumpingsystem, at a pressure less than 200 psi, and at an infusion flow ratebetween 50 and 600 ml min.

The visceral fat is preferably removed using a slow, controlled, precisemovement of the cannula over the visceral fat. Only minor bleeding isexpected, and that can be controlled by well established techniquesknown in the surgical art of laparoscopic or open surgery.

The embodiments that are optimized for removing visceral fat may be usedduring gastric bypass surgeries, or as stand alone procedures for obesepatients who do not qualify for gastric bypass surgery, especially forindividuals with poorly controlled diabetes mellitus type II.Additionally, visceral fatty tissue lipectomy described in connectionwith these embodiments can be performed as a medical procedure for theprevention of diabetes mellitus type II and cardiovascular disease inpatients with significant stores of visceral fat.

The embodiments described above may be used in various liposuctionprocedures including, without limitation, liposuction of the face, neck,jowls, eyelids, posterior neck (buffalo hump), back, shoulders, arms,triceps, biceps, forearms, hands, chest, breasts, abdomen, abdominaletching and sculpting, flanks, love handles, lower back, buttocks,banana roll, hips, saddle bags, anterior and posterior thighs, innerthighs, mons pubis, vulva, knees, calves, shin, pretibial area, anklesand feet. They may also be used in revisional liposuction surgery toprecisely remove residual fatty tissues and firm scar tissue (areas offibrosis) after previous liposuction.

The embodiments described above may also be used in conjunction withother plastic surgery procedures in which skin, fat, fascia and/ormuscle flaps are elevated and/or removed as part of the surgicalprocedure. This would include, but is not limited to facelift surgery(rhytidectomy) with neck sculpting and submental fat removal, jowlexcision, and cheek fat manipulation, eyelid surgery (blepharoplasty),brow surgery, breast reduction, breast lift, breast augmentation, breastreconstruction, abdominoplasty, body contouring, body lifts, thighlifts, buttock lifts, arm lifts (brachioplasty), as well as generalreconstructive surgery of the head, neck, breast abdomen andextremities. It will be further appreciated that the embodimentsdescribed above have numerous applications outside the field ofliposuction.

The embodiments described above may be used in skin resurfacing of areasof the body with evidence of skin aging including but not limited to sundamage (actinic changes), wrinkle lines, smokers' lines, laugh lines,hyper pigmentation, melasma, acne scars, previous surgical scars,keratoses, as well as other skin proliferative disorders.

The embodiments described above may target additional tissue typesincluding, without limitation, damaged skin with thickened outer layersof the skin (keratin) and thinning of the dermal components (collagen,elastin, hyaluronic acid) creating abnormal, aged skin. The cannulawould extract, remove, and target the damaged outer layers, leavingbehind the healthy deep layers (a process similar to traditionaldermabrasion, chemical peels (trichloroacetic acid, phenol, croton oil,salicyclic acid, etc.) and ablative laser resurfacing (carbon dioxide,erbium, etc.) The heated stream would allow for deep tissue stimulation,lightening as well as collagen deposition creating tighter skin, withimprovement of overall skin texture and/or skin tone with improvementsin color variations. This process would offer increased precision withdecreased collateral damage over traditional methods utilizing settingsand delivery fluids which are selective to only the damaged targettissue.

Other implementations include various distal tip designs and lighterpressure settings that may be used for tissue cleansing particularly inthe face but also applied to the neck, chest and body for deep cleaning,exfoliation and overall skin hydration and miniaturization. Higherpressure settings may also be used for areas of hyperkeratosis, callusformation in the feet, hands knees, and elbows to soften, hydrate andmoisturize excessively dry areas.

Additional tissue removal procedures may be accomplished by variousother embodiments. For example, cannula designs with lower pressuresettings including lower suction pressure and an atraumatic stream withgentle boluses may be used to selectively remove viable fat cells(adipocytes) which can be extracted and processed for re-injection intoareas of fat deficiency. This would include, without limitation, areasaround the face, brow, eyelids, tear troughs, smile lines, nasolabialfolds, labiomental folds, cheeks, jaw line, chin, breast, chest abdomen,buttocks, arms, biceps, triceps, forearms, hands, flanks, hips, thighs,knees, calves, shin, feet, and back. A similar method may be used toaddress post liposuction depressions and/or concavities from overaggressive liposuction. Other procedures utilizing a similar methodinclude; without limitation, breast augmentation, breast lifts, breastreconstruction, general plastic surgery reconstruction, facialreconstruction, reconstruction of the trunk and/or extremities.

Additional uses include tissue removal in the spine or spinalnucleotomy. The cannula used in spinal nucleotomy procedures includesheated solution supply tubes within the cannula as described above. Thecannula further includes a flexible tip capable of moving in multipleaxes, for example, up, down, right and left. Because of the flexibletip, a surgeon may insert a cannula through an opening in the annulusfibrosis and into the central area, where the nucleus pulpous tissue islocated. The surgeon can then direct the cannula tip in any direction.Using the cannula in this manner the surgeon is able to clean out thenucleus pulpous tissue while leaving the annulus fibrosis and nervetissue intact and unharmed.

In another implementation, the present design can be incorporated in toan endovascular catheter for removal of vascular thrombus andatheromatous plaque, including vulnerable plaque in the coronaryarteries and other vasculature.

In another implementation, a cannula using the present design can beused in urologic applications that include, but are not limited to,trans-urethral prostatectomy and trans-urethral resection of bladdertumors.

In another implementation, the present design can be incorporated into adevice or cannula used in endoscopic surgery. An example of one suchapplication is chondral or cartilage resurfacing in arthroscopicsurgery. The cannula can be used to remove irregular, damaged, or torncartilage, scar tissue and other debris or deposits to generate asmoother articular surface. Another example is in gynecologic surgeryand the endoscopic removal of endometrial tissue in proximity to theovary, fallopian tubes or in the peritoneal or retroperitoneal cavities.

In yet a further implementation to treat chronic bronchitis andemphysema (COPD), the cannula can be modified to be used in the manner abronchoscope is used; the inflamed lining of the bronchial tubes wouldbe liquefied and aspirated, thereby allowing new, healthy bronchial tubetissue to take its place.

The various embodiments described each provide at least one of thefollowing advantages: (1) differentiation between target tissue andnon-target tissue; (2) clog resistance, since the liquid projected in adistal-to-proximal direction across the suction orifices, whichgenerally prevents the suction orifice or the cannula from clogging orbecoming obstructed; (3) a reduction in the level of suction compared totraditional liposuction, which mitigates damage to non-target tissue;(4) a significant reduction in the time of the procedure and the amountof cannula manipulation required; (5) a significant reduction in surgeonfatigue; (6) a reduction in blood loss to the patient; and (7) improvedpatient recovery time because there is less need for shearing of fattytissue during the procedure.

Although the present invention has been described in detail withreference to certain implementations, other implementations are possibleand contemplated herein.

All the features disclosed in this specification may be replaced byalternative features serving the same, equivalent, or similar purpose,unless expressly stated otherwise. Thus, unless expressly statedotherwise, each feature disclosed is one example only of a genericseries of equivalent or similar features.

1. A method of removing visceral fat from a subject using a cannula thathas a longitudinal axis that runs in a proximal-to-distal direction, thecannula having an interior cavity and an orifice that is configured topermit material to enter the interior cavity, the method comprising thesteps of: generating a negative pressure in the interior cavity so thatthe negative pressure draws a portion of the visceral fat, in adirection that is perpendicular to the longitudinal axis, into theinterior cavity via the orifice, wherein the orifice is substantiallyparallel to the longitudinal axis; delivering fluid, via a conduit, sothat the fluid exits the conduit within the interior cavity and impingesagainst the portion of the visceral fat that was drawn into the interiorcavity, wherein the fluid is delivered as a series of pulses at apressure between 600 and 1300 psi and at a temperature between 100° F.and 140° F., so as to soften, liquefy, or gellify the visceral fat; andsuctioning away the visceral fat that has been softened, liquefied, orgellified.
 2. The method of claim 1, wherein the fluid is delivered at atemperature of about 120° F.
 3. The method of claim 1, wherein the fluidis delivered at a pulse rate of between 25 and 60 pulses per second. 4.The method of claim 3, wherein the pulses are delivered with a dutycycle between 30 and 80 percent.
 5. The method of claim 4, wherein thefluid is delivered at a temperature of about 120° F. and the fluid isdelivered as a series of pulses at a pressure between 900 and 1300 psi.6. The method of claim 1, wherein the fluid is traveling in asubstantially distal to proximal direction just before it impingesagainst the portion of the visceral fat that was drawn into the interiorcavity.
 7. The method of claim 1, wherein the fluid is delivered as aseries of pulses at a pressure between 900 and 1300 psi.